CHM152 Quiz 3
25 Pts
Show all work to receive credit.
Fall 2018
1. (2 Pts) For the following reaction at equilibrium, which gives a change that will shift the position
of equilibrium to favor formation of more products?
~
2NOBr(g) ~ 2NO(g) + Br2(g),
MI0 rxn = 30 kJ/mol
~ Remove Br2.
B) Increase the total pressure by decreasing the volume.
C) Remove NOBr selectively.
D) Add more NO.
E) Lower the temperature.
2. (4 Pts) What is the equilibrium constant, Kc, for an e_guilibrium mixture, for the reaction
fl
c~
@
8
:::. ThJ [a;t = . ,o. --:· •- :::: 1J__
2BrCb(g) =;: Br2(g) + 3Ch(g) that was found to contain 1.0 mol BrCb, 2.0 mol Br2 and 6.0 mol
Ch in a 6.0 L vessel.
~
3
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l<
f-<;;,O
i;
r81CR_ 7~
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L
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0_7 ~
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1
3. (5 Pts) The solubility of silver bromide can be increased by dissolving it in a solution containing the
thiosulfate anion.
K1 = 7.7 x 10-13
AgBr(s) ~..Ag"{aq) + Br-(aq)
3
~aq)+2S2Oi-(aq) ~ Ag(S2O3)2 -(aq)
K2=4.7x 1013
4. (4 Pts) Carbon tetrachloride reacts at high temperatures with oxygen to produce two toxic gases,
phosgene and chlorine.
,t.._
CCl4(g) + (1/2)O2(g) - r COCh(g) + Ch(g), Kc = 4.4 x 109 at 1,000 K
Calculate Kc for the reaction 2CCl4(g) + O2(g)
5;f\t4
+hq
C'ec__bfl&
k =={!5''-,f
,t.._
-""?
2COCh(g) + 2Ch(g).
Ree<-c.,,f,d'n is the
li/x10V:,;;:;
r:1·r:,f
l'ece_c+1J-n
d.:,L-Lhk&,.
/,9x1ol?
More Question on Back
5. (3 Pts) At 700 K, the reaction 2SO2(g) + O2(g) ~ 2SO3(g) has the equilibrium constant Kc= 4.3 x
106 , and the following concentrations are present: [SO2] = 0.10 M; [SO3] = 10. M; [02] = 0.10 M.
Which of the following is true based on the above? YOU MUST SHOW A CALCULATION TO
PORT YOUR ANSWER.
Qc < Kc, the reaction proceeds from left to right to reach equilibrium
Qc > Kc, the reaction proceeds from left to right to reach equilibrium
C) Qc < Kc, the reaction proceeds from right to left to reach equilibrium
rL~ -._.
D) Qc = Kc, the reaction is currently at equilibrium
~ Gfr\ -f-ww rr,-• , . ·E) Qc > Kc, the reaction proceeds from right to left to reach equilibrium ,:;;-
/,, 6 X / a
r;
6. (2 Pts) Write the correct equilibrium constant expression for the following reaction?
FeO(s) + H2(g)
"--~
Fe(s) + H2O(g)
)cc=-
[l1~r.D
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7. (5 Pts) 1.75 moles of H2O2 were placed in a 2.50 L reaction chamber at 307°C. After equilibrium
was reached, 1.20 moles of H2O2 remained. Calculate the equilibrium constant, Kc, for the reaction
2H2O2(g)
.I
(:
"--~
2H2O(g) + O2(g).
0, 7fl\
-~
0
0
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~)(
r; 0, 1M-i'l-- -;..OrY~
~
X
I
I,
7-- = 04
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